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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,135 records · Page 63

Technologies for node-degree based clustering of data sets

Technologies for node-degree based clustering include a computing device to construct a graph that includes multiple vertices corresponding to the data points of a data set. The computing device inserts an edge between each pair of vertices that has a corresponding similarity metric that meets a predetermined threshold similarity metric. The computing device determines a node degree for each vertex in the graph and initializes a cutoff node degree as the lowest node degree of the vertices. The computing device selects a test subset of the graph that includes vertices having a node degree less than or equal to the cutoff node degree. The computing device determines whether the test subset covers the graph and if not increases the cutoff node degree. If the test subset covers the graph, the data points corresponding to the vertices of the test subset are the representative cluster. Other embodiments are described and claimed.

Sitik, Ahmet Can↗

Environmental test program for superconducting materials and devices

A systematic approach to obtaining real time, superconducting YBa2Cu30(7-x) materials is presented. The work was carried out under the overall direction of Clemson University with tasks being performed at both Clemson and Westinghouse (Aiken, SC). Clemson prepared the tapecast superconducting 123 material and fabricated in into substrate-supported, environmentally-protected conducting links. Following this, all of the elements were individually tested for resistance vs. temperature and Tc; and then a portion of them were kept at Clemson for further testing while a randomly selected group was delivered to Westinghouse for specialized testing and evaluation in their low temperature/high vacuum and radiation facilities. In addition, a number of control samples (12 ea.) were put on the shelf at Clemson for further reference at the end of the testing period. The specific tests conducted at Clemson and Westinghouse/SRC are presented with a summary of the results.

Haertling, Gene↗

Universal approach to analysis of cavitation and liquid-impingement erosion data

Cavitation erosion experimental data was analyzed by using normalization and curve-fitting techniques. Data were taken from experiments on several materials tested in both a rotating disk device and a magnetostriction apparatus. Cumulative average volume loss rate and time data were normalized relative to the peak erosion rate and the time to peak erosion rate, respectively. From this process a universal approach was derived that can include data on specific materials from different test devices for liquid impingement and cavitation erosion studies.

Rao, P. V.↗

U.S. Navy Wave Energy Test Site – Early Findings.

The U.S. Navy’s Wave Energy Test Site (WETS), with three test berths at 30, 60, and 80m water depths, located on the windward side of the island of Oahu, Hawaii, in now fully operational. The first such grid-connected test site in the U.S., WETS has hosted two wave energy conversion (WEC) devices since its June 2015 commissioning – the Fred. Olsen Lifesaver (Figure 1) and Northwest Energy Innovations Azura. Both are point absorber WECs, but with very different configurations and power take off (PTO) strategies. Several additional devices will be tested at WETS in the coming years, beginning with an oscillating water column device from Ocean Energy in late 2017.

16 TIDAL AND WAVE POWER↗

NREL's Improved Linearity Testing of Photovoltaic Reference Cells

Photovoltaic devices are characterized under standard testing conditions that include a defined reference spectrum and total irradiance. International standards for reference cell calibrations require that reported reference cell response (typically Isc) vs. total irradiance must be linear. How can linearity be efficiently determined? In 2006 NREL developed a test bed, based on the "two-lamp method" that provided a low cost, but low accuracy method for determining whether cell response was linear with irradiance. This paper describes very simple changes to NREL's historical method [1] for determining linearity that yield greatly improved results. It also describes a method that can be used to quantify and correct for non-linearity.

41 EE - Solar Energy Technologies Office (EE-4S)↗

Verification and Validation Testing of the Bridle and Umbilical Device for Mars Science Laboratory

The Bridle Umbilical Device (BUD) subsystem is used during the Skycrane maneuver of the Mars Science Laboratory (MSL) during the final phases of the Entry Descent and Landing (EDL). During this phase the BUD subsystem will control the deployment of the MSL Rover from the Descent Stage. This paper covers the verification and validation testing of the subsystem. Testing included component through full system level testing. Testing ranged from simple bench top extraction tests to full system deploy drop test that included external disturbances such as the Rover mobility impulse. This paper will discuss the test that were performed, why they were performed and how these test results were used in the overall Verification and Validation of the MSL Skycrane phase.

Gallon, John↗

Total Dose Effects in Conventional Bipolar Transistors

This paper examines various factors in bipolar device construction and design, and discusses their impact on radiation hardness. The intent of the paper is to improve understanding of the underlying mechanisms for practical devices without special test structures, and to provide (1) guidance in ways to select transistor designs that are more resistant to radiation damage, and (2) methods to estimate the maximum amount of damage that might be expected from a basic transistor design. The latter factor is extremely important in assessing the risk that future lots of devices will be substantially below design limits, which are usually based on test data for older devices.

Bipolar Devices Cassini Ionizing radiation effects↗

Thermionic emission and energy conversion

This project worked on development of a transformative heat-to-electricity conversion device based on thermionic energy conversion. The research provided a unique opportunity to transform the thermionics technology of the 1950-1990s by applying modern materials and 21st century wafer-scale fabrication methods. Research was conducted to further development of a thermionic energy converter based on modern microfabrication and new low work function anode materials that can surpass all other forms of direct heat-to-electricity conversion. This project completed the following goals: (1) Developed components for use in thermionic energy converters and electron emission devices, including electrode materials for electron emission and electron absorption with ultimate work functions below 5 eV; (2) Designed and fabricated thermionic devices for energy conversion and electron emission based on the components developed in (1); (3) Engineered test systems to characterize electronic, thermal, and mechanical properties of thermionic devices and electron emitters and their components, and test devices and components designed and fabricated in (1) and (2); and (4) Developed theoretical modeling capabilities in support of these technical objectives.

36 MATERIALS SCIENCE↗

GrayQb TM Single-Faced Version 2 (SF2) Open Environment Test Report (Rev. 1)

This report details the design upgrades incorporated into the new version of the GrayQb TM SF2 device and the characterization testing of this upgraded device. Results from controlled characterization testing in the Savannah River National Laboratory (SRNL) R&D Engineering Imaging and Radiation Lab (IRL) and the Savannah River Site (SRS) Health Physics Instrument Calibration Laboratory (HPICL) is presented, as well as results from the open environment field testing performed in the E-Area Low Level Waste Storage Area. Resultant images presented in this report were generated using the SRNL developed Radiation Analyzer (RAzer TM ) software program which overlays the radiation contour images onto the visual image of the location being surveyed.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

SU-E-T-260: Development of a System to Verify for Connection Consistency in a Brachytherapy

Purpose: Brachytherapy has multiple manual procedures which are prone to human error, especially during the connection process of the treatment device to applicator. This is when considerable attention is required. In this study, we propose a new connection verification device concept. Methods: The system is composed of a ring magnet (anisotropic ferrite : magfine Inc), hole device (A1324LUA-T : Allegro MicroSystems Phil Inc) and an in-house check cable, which is made from magnetic material (Figure1). The magnetic field distribution is affected by the check cable position and any magnetic field variation is detected by the hole device. This system frequency is 20Hz and the average of 4 signals was used as hole device value to reduce noise. Results: The value of the hole device is altered, depending on the location of the check cable. The resolution of the check cable position is 5mm and 10mm, around a 10mm region from the hole device and over 10mm, respectively. There was a reduction in sensitivity of the hole device, in our test, which was linked to the distance of the hole device from the check cable. Conclusion: We demonstrated a new concept of connection verification in a brachytherapy. This system has the possibility to detect an incorrect connection. Moreover, the system is capable of self-optimization, such as determining the number of hole device and the magnet strength.Acknowledgement:This work was supported by JSPS Core -to-Core program Number 23003 and KAKENHI Grant Number 26860401. This work was supported by JSPS Core-to-Core program Number 23003 and KAKENHI Grant Number 26860401.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Mitigation of High Altitude and Low Earth Orbit Radiation Effects on Microelectronics via Shielding or Error Detection and Correction Systems

The NASA Cooperative Agreement NAG4-210 was granted under the FY2000 Faculty Awards for Research (FAR) Program. The project was proposed to examine the effects of charged particles and neutrons on selected random access memory (RAM) technologies. The concept of the project was to add to the current knowledge of Single Event Effects (SEE) concerning RAM and explore the impact of selected forms of radiation on Error Detection and Correction Systems. The project was established as an extension of a previous FAR awarded to Prairie View A&M University (PVAMU), under the direction of Dr. Richard Wilkins as principal investigator. The NASA sponsored Center for Applied Radiation Research (CARR) at PVAMU developed an electronic test-bed to explore and quantify SEE on RAM from charged particles and neutrons. The test-bed was developed using 486DX microprocessor technology (PC-104) and a custom test board to mount RAM integrated circuits or other electronic devices. The test-bed had two configurations - a bench test version for laboratory experiments and a 400 Hz powered rack version for flight experiments. The objectives of this project were to: 1) Upgrade the Electronic Test-bed (ETB) to a Pentium configuration; 2) Accommodate more than only 8 Mbytes of RAM; 3) Explore Error Detection and Correction Systems for radiation effects; 4) Test modern RAM technologies in radiation environments.

Gupta, Kajal↗

Environmental test program for superconducting materials and devices

This report is divided into two parts. The first dealing with work involved with Clemson University and the second with the results from Westinghouse/Savannah River. Both areas of work involved low noise, low thermal conductivity superconducting grounding links used in the NASA-sponsored Spectroscopy of the Atmosphere using Far Infrared Emission (SAFIRE) Project. Clemson prepared the links from YBa2Cu3O(7-x) superconductor tape that was mounted on a printed circuit board and encapsulated with epoxy resin. The Clemson program includes temperature vs. resistance, liquid nitrogen immersion, water immersion, thermal cycling, humidity, and radiation testing. The evaluation of the links under a long term environmental test program is described. The Savannah River program includes gamma irradiation, vibration, and long-term evaluation. The progress made in these evaluations is discussed.

Haertling, Gene↗

Compendium of Current Single Event Effects for Candidate Spacecraft Electronics for NASA

NASA spacecraft are subjected to a harsh space environment that includes exposure to various types of ionizing radiation. The performance of electronic devices in a space radiation environment are often limited by their susceptibility to single event effects (SEE). Ground-based testing is used to evaluate candidate spacecraft electronics to determine risk to spaceflight applications. Interpreting the results of radiation testing of complex devices is and adequate understanding of the test condition is critical. Studies discussed herein were undertaken to establish the application-specific sensitivities of candidate spacecraft and emerging electronic devices to single-event upset (SEU), single-event latchup (SEL), single-event gate rupture (SEGR), single-event burnout (SEB), and single-event transient (SET). For total ionizing dose (TID) and displacement damage dose (DDD) results, see a companion paper submitted to the 2015 Institute of Electrical and Electronics Engineers (IEEE) Nuclear and Space Radiation Effects Conference (NSREC) Radiation Effects Data Workshop (REDW) entitled "compendium of Current Total Ionizing Dose and Displacement Damage for Candidate Spacecraft Electronics for NASA by M. Campola, et al.

spacecraft electronics↗

Satellite Test of Radiation Impact on Ramtron 512K FRAM

The Memory Test Experiment is a space test of a ferroelectric memory device on a low Earth orbit satellite. The test consists of writing and reading data with a ferroelectric based memory device. Any errors are detected and are stored on board the satellite. The data is send to the ground through telemetry once a day. Analysis of the data can determine the kind of error that was found and will lead to a better understanding of the effects of space radiation on memory systems. The test will be one of the first flight demonstrations of ferroelectric memory in a near polar orbit which allows testing in a varied radiation environment. The memory devices being tested is a Ramtron Inc. 512K memory device. This paper details the goals and purpose of this experiment as well as the development process. The process for analyzing the data to gain the maximum understanding of the performance of the ferroelectric memory device is detailed.

MacLeod, Todd C.↗

Testing methods and techniques: Strength of materials and components. A compilation

The methods, techniques, and devices used in testing the mechanical properties of various materials are presented. Although metals and metal alloys are featured prominently, some of the items describe tests on a variety of other materials, from concrete to plastics. Many of the tests described are modifications of standard testing procedures, intended either to adapt them to different materials and conditions, or to make them more rapid and accurate. In either case, the approaches presented can result in considerable cost savings and improved quality control. The compilation is presented in two sections. The first deals specifically with material strength testing; the second treats the special category of fracture and fatigue testing.

Source record↗

Single-Event Effect Report for EPC Series eGaN FETs: Comparison of EPC1000 and EPC2000 Series Devices for Destructive SEE

Recent testing of the EPC1000 series eGaN FETs has shown sensitivity to Single Event Effects (SEE) that are destructive. These effects are most likely the failure of the very thin gate structure in HEMT architecture. EPC has recently changed the doping of the substrate to improve the performance and the SEE response. This testing compares the SEE response of both devices.

Scheick, Leif↗

Liquid salt environment stress-rupture testing

Disclosed herein are systems, devices and methods for stress-rupture testing selected materials within a high-temperature liquid salt environment. Exemplary testing systems include a load train for holding a test specimen within a heated inert gas vessel. A thermal break included in the load train can thermally insulate a load cell positioned along the load train within the inert gas vessel. The test specimen can include a cylindrical gage portion having an internal void filled with a molten salt during stress-rupture testing. The gage portion can have an inner surface area to volume ratio of greater than 20 to maximize the corrosive effect of the molten salt on the specimen material during testing. Also disclosed are methods of making a salt ingot for placement within the test specimen.

36 MATERIALS SCIENCE↗

The damage equivalence of electrons, protons, and gamma rays in MOS devices

The results of laboratory tests to determine the radiation damage effects induced on MOS devices from Co-60, electron, and proton radiation are reported. The tests are performed to establish the relationship between the Co-60 gamma rays and the level of damage to the MOS devices in regards to different damages which can be expected with the electron and particle bombardments experienced in space applications. CMOS devices were exposed to the Co-60 gamma rays, 1 MeV electrons, and 1 MeV protons while operating at 3, 10, and 15 V. The test data indicated that the Co-60 source was reliable for an initial evaluation of the electron damages up to 2 MeV charge. A correction factor was devised for transferring the Co-60 measurements to proton damages, independent of bias and transistor types, for any orbit or environment.

Brucker, G. J.↗